Taken on the seventh
shuttle mission in June 1983, this was one of the most interesting
oceanography photographs from the early missions. It alerted NASA photograph
interpreters to the oceanographic possibilities of the shuttle Earth
Observation Project. Four wave packets can be seen off the island of
Hainan in the South China Sea. White sandy beaches along the coast
of Hainan can be seen in top left, partly obscured by the clouds that
run down the left of the frame.

Such wave packets
are best viewed when coming into contact with the continental shelf, and
each wave packet imaged in this scene reflects one diurnal tide sequence.
This differs considerably from the wave packets in slide
#13, where one packet was produced every 24 hours and the packets
were subjected to forcing through the confines of the Strait of Gibraltar
and subsequently fanned out into the Mediterranean. In the shallow waters
flowing over the continental shelf in the Gulf of Tongking, the waves
obtain an amplitude of no more than 30 to 40 meters.